The characterisation of a new system based on cashew-nut tree gum, a branch
ed acidic heteropolysaccharide found in Brazil, and poly(ethylene glycol) (
PEG) was studied. Phase diagrams are provided for the PEG-cashew-nut tree g
um system. The influence of PEG molecular mass, tie-line length and pH on b
ovine serum albumin (BSA) partition was investigated. Protein partition coe
fficient was little influenced by changing PEG molecular mass. Increasing t
he tie-line length decreased the partition. Increasing the pH also raised t
he BSA partition coefficient. It is shown that systems formed by PEG and ca
shew-nut tree gum may be considered as an interesting alternative for use i
n protein purification. (C) 2000 Elsevier Science B.V. All rights reserved.